Systems and Methods for Talk Group Distribution

1. A method for notifying a user of communications group events, the method comprising the acts of: receiving, by a group list management server from a first user, a subscription request to communications group events; determining, by the group list management server, that a communications group event associated with the first user has occurred; determining, by the group list management server, that the first user subscribes to authorization events for particular communication group events; sending, by the group list management server to the first user, a request for authorization associated with the communications group event; and sending a notification by the group list management server to the first user of the communications group event when the first user authorizes the communications group event.

2. The method of claim 1 , further comprising the act of: determining whether the first user is available, wherein the act of notifying the first user is deferred until the first user is available.

3. The method of claim 1 , wherein the communications group event is the addition of the first user to an existing communications group.

4. The method of claim 1 , wherein the communications group event is the removal of the first user from an existing communications group.

5. The method of claim 1 , wherein the communications group event is the addition of the first user to a new communications group.

6. The method of claim 1 , wherein the request for notification is included in a session initiation protocol (SIP) Subscribe message.

7. The method of claim 1 , wherein the act of determining that a communications event has occurred comprises the act of: monitoring documents for addition or deletion of the first user from an existing communications group, or for addition of the first user to a new communications group.

8. The method of claim 7 , wherein the documents are extensible markup language (XML) documents.

9. The method of claim 1 , further comprising the acts of: receiving, from the first user, a request for additional information regarding the communications group event; and providing the additional information to the first user.

10. The method of claim 9 , wherein the additional information includes a membership of a communications group associated with the communications group event.

11. The method of claim 1 , wherein communications groups includes a user with two different types of communication addresses.

12. The method of claim 11 , wherein the two different types of communications addresses are selected from the group consisting of an electronic mail address, telephone number, instant messaging identifier, dispatch station identifier, dispatch group identifier, short messaging service (SMS) identifier, and multimedia service (MMS) identifier.

13. The method of claim 1 , wherein the notification is sent by session initiation protocol (SIP), wireless access protocol (WAP), short message service (SMS), multimedia message service (MMS), push access protocol (PAP), or SyncML.

14. The method of claim 1 , wherein the request for notification is received by a group management server from a web portal.

15. The method of claim 14 , further comprising the acts of: receiving, by the group management server from the web portal, one of a request to create a group, retrieve information about a group, update information about a group or delete a group.

16. A method for notifying a user of a communications group event, the method comprising the acts of: monitoring a document that includes information related to communications groups; determining that changes have been made to the document; identifying a user affected by the changes to the document; determining that the affected user subscribes to changes to the document and to authorization events for changes to the document; sending, to the affected user, a request for authorization for the changes to the document; and sending a notification to the affected user of the changes to the document when the affected user authorizes the changes to the document.

17. The method of claim 16 , further comprising the acts of: identifying another user affected by the changes; determining whether the another user has requested notifications; and notifying the another user only if the another user has requested notifications.

18. The method of claim 16 , wherein the change is an addition of a user to a particular communications group.

19. The method of claim 16 , wherein the document is an extensible markup language (XML) document.

20. The method of claim 16 , wherein the notification to the affected user provides an option to reject membership in a communications group.

21. The method of claim 16 , wherein the notification to the affected user provides an option to accept membership in a communications group.